Milan Králik

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• Assoc. Prof.
• Senior Researcher at Slovak University of Technology in Bratislava

This study focuses on the effectiveness of a new substance in stabilizing paper information carriers - hydrotalcite applied to the paper in a partially polar environment. The effect of modification on the stabilization of paper during accelerated aging was investigated by measuring chemical (surface pH, rate of glycosidic bond cleavage), mechanical...

This overview provides insights into organic and metal–organic polymer (OMOP) catalysts aimed at processes carried out in the liquid phase. Various types of polymers are discussed, including vinyl (various functional poly(styrene-co-divinylbenzene) and perfluorinated functionalized hydrocarbons, e.g., Nafion), condensation (polyesters, -amides, -an...

Oxidation of cyclopentanone (CPO) was studied over metal-free carbon catalysts in solvent-free conditions. Norit SX plus (900 m2 g−1) and Vulcan XC72 (240 m2 g−1) were used as pristine materials. Catalysts were prepared by activation in nitrogen and by treatment with urea, calcined in nitrogen at 500 °C and 950 °C. SEM, EDX, XPS, X-ray powder difra...

The aminocarbonylation of 4-iodoanisole with morpholine using the palladium catalysts supported on biodegradable polyurea was investigated. Kinetic measurements carried out in mechanically stirred reactor allowed to estimate a reaction rate (TOF) 34.3 ± 4.2 mol Anis-I Pd.mol⁻¹ h⁻¹ at 130 °C and CO gas pressure of 8 bar. The calculated activation en...

Preservation of cellulose cultural objects, particularly books, is a field of research with about 100 years of history. The most dangerous in terms of their lifespan is the use of acidic wood-based paper which represents a problem in both quality and durability. Acid hydrolysis of polymeric cellulose chains is a key factor responsible for loss of v...

Hydrotalcite samples were prepared in the form of powder and/or sol under different conditions and characterised by various techniques. A suitable system of liquid carriers consisting of perfluoroheptane, isopropanol, and water (PFH-IPA-H 2 O) was chosen to apply HTlcs as deacidifying agents on paper. The areas of miscibility and immiscibility in t...

This minireview discusses the use of zeolites as catalysts in all stages of lignocellulose biomass (LCB) valorization process. A summary of some synthesis and characterization methods for zeolitic materials is provided. Utilization of various active sites of zeolites is explored with the focus on Brønsted and Lewis acid sites and the importance of...

Oxidation of cyclopentanone (CPO) was studied over metal-free carbon catalysts in solvent-free conditions. Two pristine carbons were used: activated carbon Norit SX plus (total BET surface area 900 m ² g ⁻¹ , external surface area about 350 m ² g ⁻¹ ) and carbon black Vulcan XC72 (total BET surface area 250 m ² g ⁻¹ ). Catalysts were prepared by ac...

Stabilization and deacidification of paper information carriers is still a highly discussed topic. It is very important to continue in searching for new, more effective, and affordable methods of paper stabilization because none of the currently known processes is ideal. This study focuses on the effectiveness of a new substance in stabilizing pape...

Industrial progress in papermaking in the early nineteenth century led to the technologies that resulted in more acidic papers, which was caused mainly by the exploitation of alum (KAl(SO4)2) and rosin as sizing agents. The papers prepared by such technologies have degraded more quickly. From the 1930s various deacidification and preservation proce...

Hydrotalcite samples were prepared in the form of powder and/or sol under different conditions and characterised by various techniques. A suitable system of liquid carriers consisting of perfluoroheptane, isopropanol, and water (PFH-IPA-H2O) was chosen to apply HTlcs as deacidifying agents to paper. The areas of miscibility and immiscibility in the...

Preservation of cellulosic cultural objects, particularly books, is a field of research with about 100 years of history. The most dangerous in terms of their lifespan is the use of acidic wood-based paper, which, due to the machine production of such paper, represents a problem in terms of both quality and durability. The acid hydrolysis of polymer...

The industrial progress in papermaking in the early 19th century led to the technologies resulting in more acidic papers, which was caused mainly by exploitation of alum (KAl(SO 4 ) 2 ) and rosin. Papers prepared by such technologies have degraded more quickly. From the 1930 various deacidification and preservation processes with basic agents have...

Determination of degradation compounds of aged and deacidified papers requires an application of sev-eral analytical methods, including chromatographic and electrophoretic ones. Paper and paper extracts are very complex samples. Therefore, application of sample preparation methods is mostly involved in process of analysis. Sampling and sample prepa...

Samples of papers artificially (2 to 60 days) and naturally (10, 45, and 56 years) aged were studied by the Py-GC/MS method to identify decomposition products. Possible reaction scenarios for cellulose degradation were developed. One of the degradation products is acetic acid, which can (auto)catalyze the cleavage of cellulose β(1→4)-glycosidic bon...

This contribution presents a brief overview of the deacidification and preservation of aged cellulosic objects. Aqueous, organic liquid and air - solid/liquid systems are discussed. The global aim of all these techniques is to deliver alkaline species to acidic sites in the volume of the paper, to neutralize them and to create the so-called alkalin...

This contribution presents a brief overview of the deacidification and preservation of aged cellulosic objects. Aqueous, organic liquid and air - solid/liquid systems are discussed. The global aim of all these techniques is to deliver alkaline species to acidic sites in the volume of the paper, to neutralize them and to create the so-called alkalin...

Typical products generated during aging/degradation of cellulosic materials are carboxylic acids (e.g. formic, acetic), esters, ketones, cyclic oxygen compounds (e.g. furfural), sugars, phenolic compounds and many other volatile organic compounds. A wide set of physico chemical and analytical methods were applied to evaluate the degradation process...

This contribution refers on experimental results obtained by analysis of papersheets from old newspapers and books and accelerated aging. Relation among formation of acidic compounds, decrease in degree of polymerization, appearance (colour, glossiness) and mechanical strength are reported. Effects of environment (acidity, alkalinity, transition me...

Reactivity of various calcium carbonate samples for flue gas desulfurization was tested. Two groups of CaCO 3 samples were considered; natural limestone containing calcite phase dominantly and samples prepared by the conversion of gypsum with ammonium and carbon dioxide (precipitated CaCO 3 ) containing different amounts of calcite, aragonite and v...

The specific surface area of 9 industrial flue gas desulphurization (FGD) gypsum samples was measured by the adsorption of nitrogen (BET isotherm), mercury intrusion porosimetry and the adsorption of methylene blue from aqueous solution. The results were compared with the reactivity of the studied gypsum samples during their reaction with an aqueou...

Liquid-phase hydrogenation of 4-chloronitrobenzene (4-CNB) to 4-chloroaniline (4-CAN) under mild reaction conditions (0.6 MPa, 25 °C, methanol-diethyl ether, 1:1 vol.) over palladium and platinum catalysts containing 1 mass% of metal supported on beta zeolite (M/B) or γ-alumina (M/A) was studied. The catalysts were prepared by the incipient wetness...

Liquid phase heterogeneous catalytic processes over dispersed metals are typical by a deactivation due to leaching of metals. This leaching usually proceeds via a chemical transformation of metals, e.g. by oxidation, subsequent complexation with species of reaction environment and dissolution, or by formation of non-catalytically active species on...

Treatment of plastic waste

Oxidation

The reactivity of flue gas desulphurization gypsum with ammonium carbonate has been studied in the temperature range (20 – 50) °C. Mechanism of this reaction was suggested and the kinetics parameters characterizing the reaction were determined. A mathematical model suitable for the prediction of the conversion of gypsum was proposed. The reaction i...

Wet flue gas desulphurisation (FGD) process with ground limestone is the most frequently used technology for the Flue Gas Desulphurisation (FGD) process. This contribution is devoted to the testing of the reactivity of CaCO3 prepared from FGD gypsum (FGDG) by the reaction with ammonium sulphate. The reactivity of limestone was evaluated on the basi...

Capability of the CaCO3 (CC) prepared from the flue gas desulphurisation gypsum (FGDG) to act as a filler for the granulated ammonium nitrate fertilizer was tested. Differences in textural and crystallographic features are described. Laboratory granulation followed by a deep investigation of granulate properties (granulometry, hardness, dustiness,...

Intensive agricultural utilization of soils requires a regular and complex fertilizing. Besides nitrogen, phosphorous and potassium (NPK), sulphur is another important element for growth of plants. 1 The sulphur containing fertilizers improve a quality of grains (corns), increases the oil content of oil seeds and content of proteins in cereals, etc...

A brief survey of 4-aminodiphenylamine (ADPA) technologies is discussed, whereas timeline of individual technologies, research and implementation of rubber chemicals technologies in Slovakia is considered. Three industrially interesting ways for the preparation of 4-ADPA are evaluated: (i) reaction of 4-chloronitrobenzene (4-CNB) with aniline (An)...

This chapter deals with the pollution of surface and groundwater by oil products, i.e., prevention of their spreading, integrated approach to modeling of wastewater treatment plants (WWTP) in an oil refinery, impact assessment of effluent discharge on receiving water and removal of selected oil substances by ozonation and O3/UV processes. Slovakia...

The history of flue gas desulphurization industrial applications has started in 1931 by installing alkaline washing of flue gas in Battersea Power Station (England), whereas the oxidation of SO2 to SO3 was enhanced by an iron catalyst. The process suffered from many problems, what stemmed from not sufficient knowledge about intrinsic chemistry of o...

Dehydrogenation of isopropanol (IPOL) to acetone (AC) has attracted a recent strong attention in connection with heat pumps; i.e. utilization of a low potential heat for the endothermic dehydrogenation of IPOL, and after compression of the produced AC its exothermic hydrogenation to IPOL [1]. Our goal for research of the IPOL dehydrogenation has be...

Reactivity of energy gypsum was investigated. The method is based on the conversion reaction of aqueous suspension of gypsum with ammonium carbonate solution. Rate of the conversion of all investigated samples, including gypsum originating from flue gas desulphurization (FGD), was high and 80 % conversion was achieved during one hour. It was found...

Preface CHISA CATALYSIS Selected proceedings, the CHISA congress, Prague, August 23-27, 2014

Hydrogenation of nitrobenzene (NB) was carried out in methanol solutions (initial concentration 0.8 mol l−1) over a Pd/C catalyst (3 wt.% of Pd; reaction mixture contained 2.2 mg Pd l−1) over the pressure range of 2–4 MPa and temperature 30–70 °C in a laboratory scale batch reactor. Zero order kinetics was observed at hydrogen pressures above 2 MPa...

A short history of the relationships among adsorption, chemisorption, and catalysis with solid catalysts is reviewed. A special focus is on the development of quality and descriptions accuracy using computers, both for the modeling of elementary physical phenomena and adsorption, as well as for the solution of more complex problems like quantum che...

Aniline (AN) is an important organic chemical commodity with an annual worldwide production at levels of MT. Main applications are in polymer chemistry; however production of rubber chemicals, dyes, pharmaceuticals, and other chemical specialties is also important. Nitration of benzene (B) and hydrogenation of the generated nitrobenzene (NB) to ani...

Potassium nitrate as a fertilizer suitable for greenhouse and hydroponic applications can be prepared by the reaction of potassium sulphate with calcium nitrate. However, it may happen that simultaneously with the precipitation of gypsum (CaSO4·2H2O) also two other binary salts, viz. syngenite (K2SO4·CaSO4·H2O) and görgeyite (K2SO4·5CaSO4·H2O) can...

The effect of two types of catalysts on the activity of the catalytic hydrogenation of nitrobenzene was studied. Catalysts were prepared by the surface deposition of palladium hydroxide with a simultaneous reduction with formaldehyde in a basic environment and were characterised by X-ray powder diffraction, transmission electron microscopy, adsorpt...

This paper compares the evaluation results of 2 samples of 6PPD (N-1,3-dimethylbutyl-N' -phenyl-para-phenylenediamine) prepared by two different technologies: — 6PPD prepared by "traditional" technology — 6PPD prepared by a new, simplified technology (NASH) being tested in VUCHT a.s. The influence of the 6PPD samples on cure charactaristics of a te...

Liquid phase hydrogenation of chloronitrobenzene isomers (x-CNB x = 2, 3, 4) to the corresponding chloroanilines (x-CAN) at mild reaction conditions (0.6 MPa, 25°C, diethyl ether-methanol as solvents) over palladium and platinum catalysts containing 1 mass % of metal on trimethylammonium functionalized poly{styrene-co-divinylbenzene} (Dowex-D) was...

Solid–liquid phase equilibria of the reciprocal system K +, Mg2 +//Cl−, NO3−–H2O were studied in the temperature range 5 °C–115 °C. Phase diagrams obtained at the temperatures of 5 °C, 20 °C, 40 °C and 60 °C are presented. Data for higher temperatures are presented in a table. A semi-empirical model for the description of solid–liquid equilibrium f...

Two sets of catalysts with 1 to 10 wt.% Pd content supported on active carbon were prepared by a conventional formaldehyde method. One set was prepared from H2PdCl4 and other one with Na2PdCl4. Focus of this contribution is on comparing influence of preparation method and palladium content on a catalyst activity in nitrobenzene hydrogenation. Catal...

Preparation of potassium nitrate from magnesium nitrate and potassium chloride was investigated. Prepared potassium nitrate contains less than 0.5 % chlorides and it can be applied as environmentally friendly fertilizer in hydroponic systems. After filtration out potassium nitrate crystals from the reciprocal system K+, Mg2+//Cl-, NO3- - H2O, the m...

Peculiarities of a liquid phase hydrogenation, namely lower diffusivity of components influencing the reaction rate and deactivation of catalysts by leaching, are discussed. A focus is on hydrogenation of aromatic compounds, whereas the following processes are evaluated: (1) partial hydrogenation of benzene to cyclohexene; (2) hydrogenation of anil...

New types of fertilizers, mainly containing nitrogen, sulphur, magnesium and calcium, efficient ways for their production and finalization procedures for solid water soluble forms are discussed. Sulphur rubber vulcanization accelerators, diphenylamine and paraphenylenediamine antidegradants for polymers and oils, as well as polymer dispersions are...

Nucleation of Mg(OH)2 was investigated by measuring the electrical conductivity and pH of the Mg(NO3)2 reaction solution to which ammonia containing different amounts of NH4NO3 was added. NH4NO3 increases solubility and slows down precipitation of Mg(OH)2 in the system. Data are presented on the influence of NH4NO3 on the solubility of Mg(OH)2 at 2...

Recycling of ZnCl2 as a catalyst in the cyclocondensation of trimethylhydroquinone and isophytol to all-rac-α-tocopherol was studied. ZnCl2 was recycled at over 98 % efficiency in required purity by repeated extraction of the reaction streams with water, followed by switching of solvent to butyl acetate and then back to water. Recycled ZnCl2 had no...

The cyclocondensation of trimethylhydroquinone and isophytol to (all-rac)-α-tocopherol was studied at reduced pressure at the presence of water or (all-rac)-α-tocopherol as solvent, and ZnCl2 as catalyst. The obtained results confirm that the yield of (all-rac)-α-tocopherol can be increased at reduced pressure due to more efficient removal of react...

The results of measuring the antioxidative efficiency of stabilizers by the viscosity changes of a polymer and by the protection factor determined from differential scanning calorimetry (DSC) tests were compared. Both methods showed relatively good correspondence for most of the tested antioxidants.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The cyclocondensation of trimethylhydroquinone and isophytol to (all rac)-α-tocopherol was studied at the presence of solid catalyst and ZnCl2. The obtained results confirm that the catalytic activity of alumina and silica base catalysts is satisfactory only at the presence of ZnCl2. The strongly acidic aluminosilicates catalyze not only the cycloc...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Innovative Pd0 heterogeneous catalysts were prepared upon using cross-linked, gel-type, functional acrylic polymers as the supports, along a simple route in use in our laboratories since long. The supports were obtained by polyaddition co-polymerization of N,N-dimethylacrylamide with either 2-acrylamido-2-methylpropane sulfonic acid, methacrylic ac...

One way of conversion of benzene into a valuable component of motor fuel is hydrocycloalkylation producing cyclohexylbenzene (CHB) and dicyclohexylbenzene (DCHB). Two catalysts containing 0.2 wt. % of ruthenium were prepared using mordenite (Ru/M) and beta (Ru/B) zeolites as supports. Catalytic tests were carried out in a batch reactor at 175 and 2...

The addition of CO 2 to propylene oxide (methyl oxirane) was used to examine the effect of catalytic systems formed from Lewis bases, mainly N,N-dimethylformamide (DMF) and tributylamine (TBA), and preferentially halides of transition metals of the iron triad (CoCl 2 , FeCl 3 and NiCl 2) and some Group 2 metal halides (CaCl 2 , MgBr 2 , ZnCl 2 , Ca...

Pd-Cu bimetallic catalysts supported on the cationic resin Dowex. 1 x 4 (gel type poly(styrene-co-divinylbenzene) with -N(CH3)(3)Cl+- groups) and basic gamma-Al2O3 were prepared by ion exchange and the incipient wetness impregnation method, respectively, and tested in the liquid-phase hydrogenation of nitrates in water. Various methods of the reduc...

Gel-type resin poly-acrylonitrile (30mol%)–N,N-dimethylacrylamide (66mol%)–ethylenedimethacrylate (4mol%) (ADE) is obtained in very high yield with γ-rays-sustained polymerisation in mass. Water-swollen ADE microparticles react readily with [PdCl42−] in water to give a macromolecular complex likely to be . The material undergoes facile reduction to...

Catalysts containing 4 and 1 wt.% of palladium and copper, respectively, supported on cationic resin (DOWEX I x 4, gel type poly(styrene-co-divinylbenzene) with -N(CH3)(3)Cl-+(-) groups, particle size 100-200 mesh) were prepared and tested in the liquid-phase hydrogenation of nitrates in water. The catalyst was prepared by reduction of anionic chlo...

Supported Pd catalysts based on Pd0 nanoclusters that are homogeneously dispersed inside of organic–inorganic nanocomposites, are produced along two different synthetic routes. Pre-formed R/SiO2 composites (R: functional gel-type resin) are let to react with PdII in a suitable liquid medium to give R/SiO2/PdII materials that are readily transformed...

Results from one stage condensation reaction of nitroarenes (nitrobenzene, o-nitrotoluene, p-nitrotoluene, 4-chloro-1-nitrobenzene, 4-methoxy-1-nitrobenzene) or nitrosobenzene and carbonyl compounds (benzophenone, benzaldehyde, acetaldehyde) with carbon monoxide at the presence of water are presented. Schiff’s bases are formed by this reaction. Hig...

Oxidative dehydrogenation of methyl isobutyrate (MIA) mainly to methyl methacrylate (MMA) and methacrylic acid (MA) over an industrial oxidation catalyst designed for oxidation of isobutene to methacrolein (Mo 12 BiPMn 3,5 Fe 3 Mg 3,5 K 0,1 Si 43 O x), and a solid heteropoly acid of the summary composition (H 5 Mo 10 PV 2 O 40) at temperatures of 2...

The microporous (gel-type) functional resin co-poly-N,N-dimethylacrylamide (DMAA) (88 % mol)/methacrylic acid (MAA) (8 % mol)/N,N'-methylenebisacrylamide (MBAA) (4 % mol) (MPIF(H)) is employed as the hosting framework for the production of resin-supported Pd(0) nanoclusters. The obtained composite MPIF(-)Na(+)/Pd(0) is prepared upon reducing, in et...

Functional resins are plausible candidates for supporting catalytically active metal nanoclusters alternative, or complementary to conventional supports such as amorphous carbon, metal oxides, zeolites. Mechanical and thermal stabilities are fair and perfectly suitable to application in the realm of fine chemistry. The polymer framework turns out t...

Catalysts based on Pd nanoparticles supported on polyacrylic resins or on polyacrylic resins/silica composites are evaluated in terms of catalyst reusability and mechanical stability. Both technologically relevant features are satisfactory. Resin/silica/Pd composites exhibit an appreciable but not dramatic decrease of specific catalytic activity (3...

Catalysts based on Pd nanoparticles supported on polyacrylic resins or on polyacrylic resins/silica composites are evaluated in terms of catalyst reusability and mechanical stability. Both technologically relevant features are satisfactory. Resin/silica/Pd composites exhibit an appreciable but not dramatic decrease of specific catalytic activity (3...

Catalysts based on Pd nanoparticles supported on polyacrylic resins or on polyacrylic resins/silica composites are evaluated in terms of catalyst reusability and mechanical stability. Both technologically relevant features are satisfactory. Resin/silica/Pd composites exhibit an appreciable but not dramatic decrease of specific catalytic activity (3...

Liquid phase hydrogenation of chloronitrobenzenes to corresponding chloroanilines over Pd on carbon (Pd/C) under mild reaction conditions was studied. On the basis of ¹H, ¹³C NMR, GC-MS and HPLC analyses of reaction mixtures, the reaction pathways were evaluated. The reduction of substrates proceeds via the formation of chloro...

The polymer framework of a resin-based catalyst built up with Pd nanoclusters (ca. 3 nm) dispersed inside the nanoporous domains of a thermally stable gel-type polyacrylic resin exhibits a good chemical stability under 5 bar H(2) at 40 degrees C for reasonable contact times. Chemical and physico-chemical integrity of the polymer framework are check...

The liquid phase hydrogenation of chloronitrobenzene isomers (x-CNB, x=2, 3, 4) to corresponding chloroanilines (x-CAN) at 0.5 MPa and 25 °C was studied. Palladium catalysts containing 1 wt.% of Pd on charcoal and sulphonated poly(styrene-co-divinylbenzene) Pd/D were used. At stoichiometric consumption of hydrogen (3 mol of H2/mol of x-CNB) 85 and...

Most hydrogen peroxide is currently produced by the selective hydrogenation of 2-ethylanthraquinone (EAQ) to 2-ethylanthrahydroquinone (EAHQ), followed by treatment with dioxygen; this produces hydrogen peroxide and regenerates 2-ethylanthraquinone. We have developed novel catalysts for this process that are based on palladium supported on very lip...

A noncombustible tough poly(vinyl chloride) (tPVC) was prepared by suspension-grafted copolymerization of poly(2-ethylhexyl acrylate) (poly-EHA; elastomer) with vinyl chloride (VC). Elastomer (poly-EHA) was prepared by emulsion, mainly homopolymerization of 2-ethylhexyl acrylate at a temperature of 30 ± 0.1°C in the presence of a redox system and w...

Commercial resin supports containing aromatic nitrogen bases as functional groups have been used as macromolecular ligands for palladium(II), thus yielding insoluble macromolecule—metal complexes. Preliminary tests were run with these materials as catalysts for the preparation of hydrogen peroxide from carbon monoxide, oxygen, and water. Pretreatme...

This chapter discusses the alkylation of biphenyl with tert-butanol that has been carried out over different zeolites under liquid phase conditions. HM (17.5) and HY (15) zeolites have been found to be the most active, with a maximum biphenyl conversion near 60%. Dealuminated mordenite HM (17.5) leads to very high selectivities to 4-(tert-butyl)bip...

This chapter discusses the texture of dealuminated mordenite catalysts modified with cerium and catalytic properties in the isopropylation of biphenyl. Formation of dispersed phase of ceria in the dealuminated mordenites modified with ceria or cerium is registered by X-ray powder diffraction (XRPD). Decrease in acidity at increased content of ceria...

The preparation and catalytic applications of dispersed metal catalysts supported on organic functional polymers are presented. The advantages of these catalysts, such as the easy tailoring with respect to the nature of the used support, the “nanoscale” size control of metal crystallites by the polymer framework, the high accessibility and conseque...

The general IAWPRC kinetics extended by volatilisation and the influence of wastewater composition on oxygen transport rate was used for description of lab-scale experiments simulating a Carrousel industrial reactor. Number of model equations and parameters were reduced by introduction of "switching functions", which express pro-portions of the rea...

The use of functional resins as designable supports for palladium nanoclusters is reviewed. Data are related to the generation of Pd nanoparticles under various conditions and inside gel-type or macroporous frameworks. The combination of different physico-chemical techniques (ISEC, ESR and PGSE NMR) is illustrated as a powerful tool for evaluating...

The relationship between texture evaluated on the basis of nitrogen adsorption–desorption isotherms, acidity and catalytic activity of mordenite catalysts dealuminated to various extents and doped with cerium was investigated. The combination of the standard BET isotherm either with a consideration of the micropores, or with the Dubinin–Radushkevic...

tert-Butylation of biphenyl with tert-butanol has been studied over large-pore H-Y (15) and H-beta (25) zeolites under liquid phase conditions using cyclohexane as a solvent. The identification of main and by-products has been performed by GC-MS analysis. The main products of the alkylation reaction were mono-tert-butylbiphenyls and di-(tert-butyl)...

A state of art in ,,2001 year-knowledge" of ecological impact of methyl-tert.butyl ether - MTBE, used as a component for enhancing octane pool of gasoline, and its harmful effects on human being is briefly discussed. High potentiality of MTBE to pollute water and to be absorbed in lungs of beings (including human ones) is demonstrated through its h...

Three periods in developing of engine liquid fuels are forecasted: (i) oil products as dominant blends in gasoline (to about 2030), (ii) exploitation of natural gas and coal (2000-2100) and (iii) fuels from renewable resources, mainly in the form of biodiesel and bio-ethanol (dominating from 2020). Alkylates produced from oil intermediates as the c...

In the context with our recently published report about skeletal isomerisation of butenes present in C4 pyrolysis fraction [V. Macho, M. Kralik, L. Jurecek, E. Jurecekova, J. Balazova, Appl. Catal. A: Gen. 203 (2000) 5], the dehydration of C4 alkanols conjugated with a positional and skeletal isomerisation of the formed C4 alkenes was studied. Ther...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A new sulfur based catalytic system for the reductive carbonylation and carbonylative reduction of aromatic nitrocompounds is described. Basic compounds and salts of transition metals, e.g. vanadium, or tin, improve properties of the catalytic system. Depending on the other reaction species added, the formation of: (i) aromatic aminocompounds from...

We report on the liquid phase hydrogenation (1 M solution in methanol) of 4-nitrotoluene and 4-nitrophenol over Pd catalysts supported on anionic resins (sulphonated 4 % crosslinked poly{styrene-divinylbenzene}, 5 meq./g ion exchange capacity, particles size 0.16-0.32 mm) at room temperature and pressure 0.25-1 MPa. The initial reaction rate in the...

The use of functional resins as designable supports for metal nanoclusters [G. Schmid, G.L. Hornyak, Current Opinion in Solid State and Material Science 2 (1997) 204; G. Schmid, M. Baumle, M. Geerkens, I. Heim, C. Hoseman, T. Sawitowski, Chem. Soc. Rev. 28 (1999) 179; J.D. Aiken III, R.G. Finke, J. Mol. Catal. A: Chemical 145 (1999) 1] is reviewed,...

Butenes present in butadiene and isobutene free C4 fraction (a stream from the production of methyl-tert-butyl ether — so-called raffinate II) were isomerised over the hydrogen-chlorided and sulphated catalysts at 350–515°C. A natural clay (bentonite) and commercial γ-alumina were used as catalyst precursors. Hydrogen-chlorided catalysts were deact...

This contribution is a brief review dealing with metal catalysts prepared on functionalized polymers. The following topics will be touched: i) preparation and properties of metal catalysts based on functionalized polymers; ii) methods for the characterization of these catalysts; iii) effect of mass transport phenomena on the overall rate of a proce...

Four synthetic ion-exchange resins (AH, BH, CH, DH) of different hydrophilic/hydrophobic properties were used as supports for heterogeneous palladium catalysts (A, B, C, D). The resins contained styrene (STY) and 2-(methacryloxy)ethylsulfonic acid (MESA) as the comonomers. Either divinylbenzene (DVB: CH, DH resins) or N,N'-methylenebisacrylamide (M...